Recently, Prof. Zhang Zhuhua and Prof. Guo Wanlin's team, in collaboration with Prof. He Yongmin from The School of Chemistry and Chemical Engineering of Hunan University and Prof. Zheng Liu from Nanyang Technological University in Singapore, designed a single atomic layer noble metal catalyst by combining precise first-principles calculations and experiments. Amorphizing noble metal Chalcogenide catalysts at the single-layer limit towards hydrogen "Production" was published online in Nature Catalysis and featured on the cover of March.
It is very important to design noble metal catalyst reasonably and improve its utilization rate for industrial application. At present, noble metal catalysts with high activity and selectivity (such as platinum, palladium, etc.) are often used in the electrolysis of aquatic hydrogen, fuel cells and air cells and other energy fields. However, rare earth reserves (e.g., platinum crust content is only 5 parts per billion) and high cost (e.g., platinum 200-250 yuan /g) hinder the large-scale application of precious metal catalysts. In the automotive market, for example, in order to meet the cost control requirements of fuel cell systems, Pt content in batteries has been reduced from 0.117g /kWgross in 2018 to 0.108g /kWgross in 2020, and is expected to drop to 0.064g /kWgross in 2025. Therefore, how to improve the utilization rate of precious metals is the main direction of current research. The nanocrystallization of precious metals is an effective and universal strategy to improve the utilization rate and reduce the weight load. At present, a variety of noble metal nanostructures have been reported, ranging from large three-dimensional porous structures, two-dimensional nanosheet structures, one-dimensional nanowires, to small zero-dimensional nanoclusters and even single atom or single atom catalysts. According to this trend, the utilization of precious metals will eventually evolve into monatomic layer catalysis. That is, almost all noble metal atoms are likely to participate in the reaction as active sites.
The team in order to realize single atomic layer catalysis using two-dimensional atomic layer structure characteristics of material itself, by first principles calculation in advance to simulate the amorphous PtSex structure characteristics and structure stability of amorphous transition was predicted by theoretical calculation of the zero point, and points out that under the amorphous material may have good catalytic performance. Subsequently, low temperature crystallization strategy was used to prepare wafer-sized amorphous PtSex films with SiO2 as the substrate, which makes the single atomic layer platinum have a high atomic utilization ratio (~26 wt%). This amorphous PtSex. x < 1.3) Has a fully activated amorphous surface, easy to catalyze reactions, has a current density of nearly 100% relative to pure platinum surface, and can reliably and continuously produce hydrogen on 2-inch wafers. In addition, electrolytic cells with this PtSex electrode can produce a high current density of 1000 mA cm−2. This amorphous strategy can also be extended to other precious metals, including Pd, Ir, Os, Rh and Ru elements, proving the universality of monatomic layer catalysis.
This research is expected to expand the design of current catalyst systems and reduce the application cost of precious metal catalysts. This paper was published in Nature Catalysis, an internationally recognized top journal in the field of Catalysis. Prof. Zhuohua Zhang was the corresponding author, and postdoctoral fellow Liren Liu (now associate professor of Nanjing University of Technology) was the co-first author, along with Prof. Zhiqiang Zhao and Academician Wanlin Guo.
Link:https://www.nature.com/articles/s41929-022-00753-y